If CMAKE_MAKE_PROGRAM is not set fail with an error message instead of
crashing. Suggest calling project() or enable_language() first to
ensure that CMAKE_MAKE_PROGRAM is set.
Move the ErrorsOFF/ON common logic from CMakeLists.txt into an
ErrorsCommon file to allow other test cases to be added that do not use
the Errors test logic.
The CMakeCommands.build_command test performs output/error checking
so move it over to RunCMake to re-use the generalized infrastrucure.
This is the only test left using Tests/CMakeCommands/CMakeLists.txt
so remove it.
